An apparatus and computer program for establishing or improving eye coordination

Abstract

An apparatus and a computer software are disclosed for improving eye coordination of a patient wherein the disclosure is adapted to provide perceptual motor learning for the visual system of a patient having a first eye and a second eye. The apparatus includes a first unit for presenting at least one first vision parameter related to a visual presentation directed towards the first eye, a second unit for presenting at least one second vision parameter related to a visual presentation directed towards the second eye, and a processing unit for controlling the first unit and / or second unit; wherein the processing unit is adapted to control a manipulation of the first vision parameter and / or the second vision parameter, the manipulation is an oscillation of the first vision parameter and / or the second vision parameter and wherein at least one of the manipulations is an asymmetrically fluctuated oscillation.

Description

[0001] An apparatus and computer program for establishing or improving eye coordination

[0002] Field of the Invention

[0003] This invention pertains in general to the field of orthoptics. More particularly the invention relates to apparatus, computer program, and methods for perceptual motor learning for the visual system of a person having an eye disorder, such as poor eye coordination. Even more particularly, the invention relates to the field of establishing and / or improving eye coordination, such as establishing and / or improving binocular vision for a patient having a binocular vision disorder. A particular field of application is the therapeutic field for patients suffering from various disorders causing at least one eye of a patient to lose coordination.

[0004] Background of the Invention

[0005] Inadequate vision development or improperly developed eye muscle control can cause poor eye coordination. Poor eye coordination may also occur due to head injuries or stroke. Poor eye coordination may cause various problems such as double vision, headaches, eye and body fatigue, irritability, dizziness, and difficulty reading and concentrating. Although corrective lenses can restore normal visual acuity, they fail to compensate for certain inherent vision dysfunctions. Current vision training approaches and devices present notable limitations: certain biofeedback systems exacerbate strabismus by encouraging maladaptive ocular alignment; traditional prism-based devices offer insufficient frequency of adjustment; occlusion-based techniques lack the capacity to provide truly binocular therapy; large, cumbersome diagnostic instruments are limited primarily to analysis rather than treatment.

[0006] There has been developed modern versions to replace these vision training approaches. One of these approaches for establishing and / or improving binocular vision is described in WO2011067361 A1. The described apparatus has a set of two units, one for respectively eye, for manipulation of a vision parameter of the visual presentation, e.g. picture, movie, image. The manipulation includes oscillating or fluctuating the vision parameter within a first range. However, improvements may be considered to improve the method described.

[0007] This invention seeks to address these deficiencies of the current treatment alternatives and to furnish a superior solution for establishing and / or improving eye coordination, including treating binocular vision disorders.

[0008] Thus, there is a need for an alternative, new or improved instrument and / or method that can be used for establishing and / or improving eye coordination, such as treatment of binocular vision disorder.

[0009] Hence, an improved patient friendly medical system, apparatus and / or method, at least suitable for establishing and / or improving eye coordination and muscular training around the eye, such as treatment of binocular disorders, would be advantageous and in particular an apparatus allowing forincreased flexibility, cost-effectiveness, easy handling in particular by a home user and / or user friendliness would be advantageous. There is in particular a desire to provide such a system, apparatus and / or method for providing perceptual motor learning for the visual system of a patient having binocular vision disorder, in order to establish and / or improve binocular vision of the patient. The system, apparatus and / or method are desired to have a high patient acceptance, for instance thanks to an easy to use, desirably by a sub-conscious therapy provided. Further, a convenient way of monitoring a larger patient population, without the need for costly frequent visits to eye specialists, would be advantageous.

[0010] Summary of the Invention

[0011] Accordingly, embodiments of the present invention preferably seek to mitigate, alleviate or eliminate one or more deficiencies, disadvantages or issues in the art, such as the above-identified, singly or in any combination by providing an apparatus, a method, and a computer program according to the appended patent claims.

[0012] According to a first aspect, an apparatus for improving eye coordination of a patient is described. The apparatus may be adapted to provide perceptual motor learning for the visual system of a patient having a first eye and a second eye. The apparatus may include a first unit for presenting at least one first vision parameter related to a visual presentation directed towards the first eye and a second unit for presenting at least one second vision parameter related to a visual presentation directed towards the second eye. The apparatus may further include a processing unit for controlling the first unit and / or second unit, wherein the processing unit may be adapted to control a manipulation of the first vision parameter and / or the second vision parameter, the manipulation is an oscillation of the first vision parameter and / or the second vision parameter and wherein at least one of the manipulations is an asymmetrically fluctuated oscillation.

[0013] The apparatus may be configured for establishing and / or improving binocular vision by the perceptual motor learning for patients having binocular vision disorder.

[0014] In one example, the manipulation of the first vision parameter and / or second vision parameters may include a movement, displacement, rotation, position, size, scale of the visual presentation on at least one axis of a coordinate 2D-plane or on at least one axis of a coordinate 3D-space.

[0015] In one example, the asymmetrically fluctuated oscillation may include a first oscillating base component and a second random or noise component on top of said first oscillating base component.

[0016] In one example, the first oscillating base component may include a continuous reciprocating function, such as a sinusoidal function, a square function, triangle function or a sawtooth function. Alternatively, and / or additionally, the first oscillating base component may include a discontinuous reciprocating or stepwise function.In one example, the second random component may include at least variations in one of a frequency, an amplitude and an offset of the first base function, and / or the second noise component may include a frequency function, such as a sinusoidal function, a square function, triangle function or a sawtooth function, added on the first oscillating base function and / or the second noise component is a white noise, or a pink noise added on the first oscillating base function.

[0017] In one example, the first unit and the second unit may be part of any of a virtual reality (VR) headset, an augmented reality (AR) set, a mixed reality (MR) set, and an extended reality (XR) set.

[0018] In one example, the oscillation may be within a first range, the first range having an extreme value, such as the extreme value is wherein a binocular vision disappears for the patient.

[0019] In one example, the process unit may be configured to provide or determine a boundary value of the manipulation of the first vision parameter and the second vision parameter wherein binocular vision disappears for the patient at said boundary value, and the extreme value is less than the boundary value.

[0020] In one example, the manipulation of the first vision parameter and the second vision parameter may be done individually, such as the manipulation of the first vision parameter differing from the manipulation of the second vision parameter.

[0021] In one example, the vision parameters may include spatial parameters including dimension or position of an image data.

[0022] In one example, the first vision parameters and / or second vision parameters may be modified at least in a portion of the visual presentation, such as the entire visual presentation respectively.

[0023] In one example, the manipulation may be an image processing operation, and wherein the visual presentation is based on image data; and wherein the image data may be identical image data for the first unit and the second unit. Alternatively and / or additionally, the image data may be nonidentical image data for the first unit and the second unit, and wherein the image data is one of a picture, a movie, a game or any other arbitrary image data displayable by electronic means, and wherein the image data optionally has an additional interactive audio component.

[0024] In one example, the first vision parameters and / or second vision parameters may be a characteristic by which image data is defined, such as one or more of focus, colour, illumination, size, orientation, or contrast.

[0025] Ine one example, the first unit and / or said second unit may be adapted to bring the visual presentation in alignment with a visual axis of the first eye and second eye, respectively; and / or wherein the first vision parameter is different than the second vision parameter, or wherein the first vision parameter is equal to the second vision parameter.

[0026] In one example, the first / and or second vision parameter may include at least one vision parameter and wherein the processing unit is adapted to only one single vision parameter may bemanipulated, and further vision parameters different from the one single vision parameter are kept constant during a perceptual motor learning session.

[0027] In one example, the first / and or second vision parameter may include at least one vision parameter and wherein said processing unit is adapted to manipulate at least two of the vision parameters.

[0028] According to a second aspect, a computer program for improving eye coordination by providing perceptual motor learning for the visual system of a patient having a first and a second eye is disclosed. The computer program includes instructions which, when the program is executed by a computer, cause the computer to carry out steps:

[0029] presenting at least one first vision parameter related to a visual presentation directed towards the first eye, and / or

[0030] presenting at least one second vision parameter related to a visual presentation directed towards the second eye; and

[0031] controlling a manipulation of the first vision parameter and / or the second vision parameter, the manipulation is an oscillation of the first vision parameter and / or the second vision parameter and wherein at least one of the manipulations is an asymmetrically fluctuated oscillation.

[0032] According to a third aspect, a method for improving eye coordination by providing perceptual motor learning for the visual system of a patient having a first and a second eye is disclosed. The method includes:

[0033] presenting at least one first vision parameter related to a visual presentation directed towards the first eye, and / or

[0034] presenting at least one second vision parameter related to a visual presentation directed towards the second eye; and

[0035] controlling a manipulation of the first vision parameter and / or the second vision parameter, the manipulation is an oscillation of the first vision parameter and / or the second vision parameter and wherein at least one of the manipulations is an asymmetrically fluctuated oscillation.

[0036] Aspects of the invention may be used for treatment of patients suffering from brain disorders. For example, head injury, such as a physical head injury. A head injury may lead to loss of coordination of at least one of the eyes, which may lead to a visual disorder. Rehabilitation where the eyes get trained to retain and / or obtain at least some of the coordination may lead to both physiological and psychological improvements.

[0037] The aspects of the invention may be used for treatment of patients suffering from dyslexia. By improving eye coordination and thereby binocular vision, reading speed and concentration related to reading may be improved.

[0038] The aspects of the invention may be used for treatment of patients suffering from stroke-related brain disorders. A stroke may lead to loss of coordination of at least one of the eyes, which may lead to a visual disorder. Rehabilitation where the eyes get trained to retain and / or obtain at leastsome of the coordination may lead to both physiological and psychological improvements of stroke patients.

[0039] The aspects of the invention may be used for treatment of patients suffering from amblyopia (lazy eye) and strabismus (crossed eyes).

[0040] When manipulating visual parameters through fluctuation or oscillation, the brain, in particular the visual cortex, will adjust and create a sequence with the same pattern which may cause the eye to rest. By manipulating a first and / or second vision parameter by asymmetrically fluctuated oscillation, the brain will be challenged or defied by provoking unexpected changes which will break the pattern created by the brain. This will cause an improvement in the training or rehabilitation of an eye disorder compared to manipulating the vision parameters by only using fluctuation or oscillation.

[0041] Further embodiments of the invention are defined in the dependent claims, wherein features for the second and subsequent aspects of the invention are as for the first aspect mutatis mutandis.

[0042] The term "oscillate” as used in the context of the present application means to move or swing from side to side regularly; or to cause to move to and fro; or vibrate; or to vary between alternate extremes; or to waver between, courses of action, etc; or to undergo or produce or cause to undergo or produce oscillation. This could be applied to all vision parameters for example how to fade color / contrast / focus / light level in or out or how images are spatially moved in relation to each other.

[0043] The term "fluctuate” as used in the context of the present application means to change or cause to change position constantly; or be or make unstable; or waver or vary; or to change continually; or shift back and forth; or vary irregularly; or to move back and forth in waves

[0044] The term "vision parameter” as used in the context of the present application means a typical value of a visual presentation that is controllable in its way it is presented to at least one eye. Vision parameters are controllable and comprise e.g. focus, brightness, contrast, colour of a visual presentation as long as these vision parameters influence movement of the eye which may facilitate establishing and / or improving eye coordination. Improving eye coordination may establish and / or improve binocular vision to the extent that these vision parameters contribute at least partly to establish binocular vision. Manipulation of such vision parameters thus comprises defocus, fading, color change, sharpness, intensity change, contrast, illumination (brightness) change, etc. In certain particularly preferred embodiments, vision parameters comprise spatial parameters including dimension (such as scaling) or position of an image. Manipulation of such vision parameters may thus comprise inducing a movement, displacement, rotation, position, size or other types of spatial operation of the visual presentation, e.g. of an image presented on one or more screens. Manipulation of such vision parameters may in some embodiments be made of the entire visual presentation respectively. Alternatively, or in addition, such vision parameters are modified only in a portion of such visual presentation in some embodiments.The term "establish” as used in the context with establishing eye coordination, which may lead to establishing binocular vision, of the present application means to cause, create, start, initiate, or bring about improved eye coordination of a patient that previously lacks full eye coordination. The term "improving” as used in the context with improving eye coordination, such as improving binocular vision, of the present application means to ameliorate, make better, or achieve a better eye coordination of a patient that already has some eye coordination, but which might be improved. For patients saving some binocular vision this may include patients having a phoria (latent strabismus) that needs to be compensated. The term "establishing and / or improving binocular vision” as used in the context of the present application consequently means one of a) establishing, b) improving, or c) establishing and (then) improving binocular vision.

[0045] Visual presentations may e.g. be based on image data, such as when displayed on a screen. Alternatively, the visual presentation may have a basis in real illuminated objects presented to the eye, wherein vision parameters of the visual presentation are modifiable by optical means, e.g. spectacles that have controllable refractivity, tinting, color, etc.

[0046] Embodiments provide training of the visual cortex in order to achieve a substantially evenly matched eye vision of both eyes processed by the visual cortex. A visual presentation is provided to the eyes within the Panum's fusional space 10 (Fig. 1), i.e., with a slight variation in disparity. In some embodiments vergence eye movements are introduced to the person not being aware of the induced variation and the person's vergence capability will increase with continued training. Thus, when a patient has unequal perceptive intensity for the two eyes, suppression and amblyopia are treated in embodiments by means of forcing the person to use the suppressed or amblyopic eye. For instance, by image manipulation, a unique situation is provided for individuals with an eye disorder as each eye is provided with an image of controlled unique vision parameters, like size, position, blurriness, etc., to interpret in the visual cortex. As respectively of the two eyes is presented with unique images, the brain, i.e. more precisely the visual cortex, becomes involved to align the visual impression from each eye to obtain an aggregated comprehensive understanding. By changing and / or manipulating different image vision parameters differently for each eye, a unique situation is provided where the patient is enabled to exercise the visual cortex. In some embodiments even the ocular muscles are involved in this training to some extent, when the modified vision parameter is a spatial parameter of the image or visual presentation. However, exercise in the present context should not be confused with purely physical training of ocular muscles. In some embodiments the ocular muscles are substantially not engaged, for instance when changing the blurriness of one of the images to force the aforementioned use of the suppressed or amblyopic eye. For situations where both sensational and motoric capabilities are to be coordinated by an individual to achieve a new, higher or elevated skill or ability, improved perceptual motor learning is provided by embodiments of the invention.

[0047] Some embodiments of the invention provide for improved patient compliance, i.e. the patient performing training without being aware of the training being made.Some embodiments of the invention provide for determination of the initial diagnosis was correct, incorrect or incomplete, depending on evolvement of improvement in binocular vision. No improvement may imply that the initial diagnosis was incorrect or incomplete whereby the patient can be sent to an optician, a MD or a responsible therapist.

[0048] Some embodiments of the invention provide for training separated from patient activity, no interaction is necessary during training other than a visual contact with a visual presentation. The training may be combined with other optical measurements.

[0049] Some embodiments of the invention also provide for subliminal, sub-conscious, training and / or exercises. The patient is commonly not deliberately training or exercising; the patient is watching a visual presentation, which contents as such are attracting the attention of the patient. Such presentations that attract the attention of the patient are for instance movies, interesting presentations, entertaining presentations, and / or games, such as computer games. The visual presentation may be streamed content, such as a streamed movie or streamed pictures. The presentations may be two-dimensional (2-D) or three-dimensional (3-D) stereoscopic presentations. Some embodiments are independent of such contents of the visual presentation as such.

[0050] Some embodiments of the invention provide for a feedback of the effectivity of training and provide thus for a control of the training effectivity. By the feedback of the progress of the therapy monitoring the effectiveness of the training is provided. Efficiency of an ongoing therapy is measured from available data, for example: when training was made; how long-time training is ongoing; how quickly subject gets tired from training etc. "Cheating” by lazy subjects not performing the training or subjects not performing the training correctly is therefore detectable and can be avoided.

[0051] Some embodiments provide for training of patients, such as young people or children, without substantially boring or tiring the patients during training sessions, e.g. when playing a computer game or watching a movie.

[0052] Some embodiments provide for a feedback from the patient that they consciously follow the visual presentation, e.g. by an ongoing computer game. This ensures that the unconscious training is reliably performed without a patient evading the training.

[0053] Some embodiments provide for training in an environment that is convenient for the patient, e.g. at home. Thus, the issue is overcome that training results may not be achieved when having to perform a test or training in a stressful environment, such as a clinical environment. Some embodiments of the invention provide for a reduction of visits of doctors and / or health care providers. Training or therapy may be provided in a home environment and doctor visits are only made when necessary.

[0054] Some embodiments provide for training or therapy independent of the spatial position of the patient in relation to the visual presentation. The patient does not need to be fixated in an inconvenient position in relation to the visual presentation. As a boundary value is provided (e.g. from an optician for the specific patient) or determined at which binocular vision disappears for the patient for each specificsession, the embodiments become independent of a need to determine or ensure a specific predetermined spatial fixation of the patient in relation to the visual presentation on which training is based.

[0055] Some embodiments of the invention also provide for a capability of the system to automatically indicate and / or contact the health provider when so needed, e.g. when binocular vision is established and / or sufficiently improved.

[0056] It should be emphasized that the term "comprises / comprising” when used in this specification is taken to specify the presence of stated features, integers, steps or components but does not preclude the presence or addition of one or more other features, integers, steps, components or groups thereof.

[0057] Brief Description of the Drawings

[0058] These and other aspects, features and advantages of which embodiments of the invention are capable of will be apparent and elucidated from the following description of embodiments of the present invention, reference being made to the accompanying drawings, in which

[0059] Fig .1 is a schematic illustration of a slight misalignment of a visual axis which occurs in decompensated phorias and an illustration of the visual range, including the Panum's fusional space;

[0060] Fig. 2 is a schematic illustration of visual axis miss-alignments for developed strabismus (top); and suppressed strabismus detected with a cover test (bottom);

[0061] Fig. 3 is a lateral view of an embodiment showing an apparatus set-up;

[0062] Fig. 4 is a schematic illustration of a first display with an image, wherein a second display is provided mutatis mutandis;

[0063] Fig. 5 is a perspective view of an embodiment, wherein an image is projected on a first screen and an optical path to a patient's eye is illustrated with a dotted line, and an analogous second screen and image is illustrated with a dashed line for the corresponding optical path;

[0064] Fig. 6 is illustrating continuous fluctuation functions for each of the visual fields as they are overlapping each other to provide a varying degree of a superimposed common image;

[0065] Fig. 7 is illustrating discontinuous fluctuation functions for each of the visual fields as they are overlapping each other to provide a varying degree of a superimposed common image;

[0066] Fig. 8 is showing an image for respectively visual fields, i.e. a) a right eye and b) a left eye, or vice versa;

[0067] Figs. 9a and b are showing a superimposed common image a) without blocking device, and b) with a partly overlapping blocking device; and

[0068] Figs. 10a-h are illustrating a sequence of consecutive partly superimposed common images a) - h) where the first and second image are spatially displaced with a greater distance for each subsequent superimposed common image.Fig. 11 is an illustration for the concept of asymmetrically fluctuated oscillation.

[0069] Detailed description of embodiments of the invention

[0070] Specific embodiments of the invention will now be described with reference to the accompanying drawings. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. The terminology used in the detailed description of the embodiments illustrated in the accompanying drawings is not intended to be limiting of the invention. In the drawings, like numbers refer to like elements.

[0071] The visual system and disorders

[0072] At birth everybody has a squint (also called manifest strabismus, heterotropia or tropia). If the newborn develops normally this squint disappears within the first months of life. Thereafter, almost everybody has a phoria (also called heterophoria or latent strabismus / heterotropia / tropia / squint). This phoria is due to the physiological resting point of the eye within the ocular cavity is not identical to the visual axis being parallel. However, this phoria gives in most people not rise to any problems or symptoms. This is due to the vergence system of the eyes, i.e., the ocular motor systems ability to perform disjunctive eye movements- the vergence reserves, being able to overcome the angle of the deviation and thereby direct the eyes towards a common object of regard.

[0073] When the vergence reserves (or fusional reserves) for some reasons cannot overcome the phoria, the phoria gives rise to symptoms and asthenopia. The phoria is then called a decompensated phoria. Patients with a decompensated phoria will sometimes even see objects as double, which means that a squint is sometimes present. In addition to being called a decompensated phoria, this type of squint is also called an intermittent squint.

[0074] Young children who, for some reason, do not have equal retinal image quality may never gain binocular vision, i.e., they never get to the stage where the initial squint is overcome and becomes a phoria, and suppression and amblyopia starts developing directly. Amblyopia can, however, only develop during the critical period of visual development which is until the age of about 12-15 years of age. After that only suppression can develop.

[0075] On the other hand, binocular vision problems can also be caused by the accommodative system, i.e., the focusing system of the eyes. Some people have an accommodative system that is not able to fully focus the eyes and they suffer from accommodative insufficiency which yields symptoms of blurred images and asthenopia. Furthermore, some subjects with a high degree of hyperopia (the refractive error often called long sighted), who are not given refractive correction can develop a squint (with the later onset of suppression and amblyopia) since the accommodative system will try to overcome the refractive error. Since accommodation is linked with the vergence system, theaccommodation used to overcome the hyperopia, will induce convergence of the eyes, and if this convergence cannot be offset by the vergence system, a tropia will be the consequence.

[0076] Many people with binocular visual disorders never have those disorders improved to the fullest extent. Corrective lenses establish normal visual acuity for many people, but the underlying visual disorder persists. Lenses alone cannot compensate for some disorders.

[0077] Decompensated phorias and accommodative insufficiency can be treated with visual therapy. This type of therapy is called orthoptics or orthoptic treatment. Orthoptic treatment is aimed at treating the vergence system's capability to rotate the eyes and the accommodative system's ability to change focus. Orthoptics can even be used to treat amblyopia and suppression. Strabismus can be treated through surgery. However, surgery is expensive, invasive, and has a surprisingly low rate of effectiveness. In addition, over 85% of the operations do not provide effective treatment for strabismus. Most surgery simply treats strabismus cosmetically by physically reorienting the eyeball, but the patient is still not using both eyes together as a unit. Any underlying suppression or amblyopia which frequently accompanies strabismus remains untreated.

[0078] Amblyopia involves reduced vision in one eye, typically because of mental suppression. It is caused by inadequate visual stimulation of the brain during the critical period of visual development. Amblyopia is frequently induced by strabismus or by a high refractive error in only one eye. Primary strabismus leads to amblyopia through the neural mechanism of suppression, because the brain partially or completely ignores images coming from the crossed eye. Amblyopia results in poor visual efficiency due to decreased stereopsis and poor distance judgment. This condition is frequently treated by patching the good eye to force the brain to utilize the amblyopic eye. Recent studies indicate, however, that such treatment can induce amblyopia in the patched eye. About one-third of all people with strabismus are diagnosed for amblyopia. Strabismus and amblyopia affect about 5% of the population.

[0079] The above disorders may be caused by a lack of eye coordination. Lack of eye coordination may also give rise to other dysfunctions or related disorders.

[0080] One of these conditions may include dyslexia and its treatment. A proportion of the dyslexic population has problems with eye movement control, convergence problems and problems maintaining stable stereo vision. Treatment can be via a direct treatment effect of the training.

[0081] Treatment can be via an indirect treatment effect of the training, i.e. the visual impairment treatment facilitates a traditional treatment of the condition that is otherwise interfered with or affected by untreated visual impairments.

[0082] These are problems that the type of training / treatment the herein described method and / or device can perform has a positive impact on, such as reading speed and concentration related to reading, such as the length of time a patient could stay focused during reading. The inventors have realized that its use can be expected to have an unexpected positive impact in the treatment of dyslexia. Even dyslexics who do not have visual problems / difficulties can be treated and the expectedeffect is considered to be achieved. This could be because the brain normally can compensate for minor problems with the eyes so that the patient may not be aware of them.

[0083] Training carried out as herein described, using a device described herein, can have a positive effect on the treatment itself. In addition, having visual difficulties as a dyslexic being treated facilitates the treatment of dyslexia itself. The use of the method and / or device for therapy or in conjunction with it can eliminate circumstances that make treatment difficult. This improves, at least unexpectedly, the prospects for traditional treatment of dyslexia in patients.

[0084] Another aspect relates to treatment of patients suffering from brain disorders. For example, head injury, such as a physical head injury. A head injury may lead to loss of coordination of at least one of the eyes, which may lead to a visual disorder. Rehabilitation where the eyes get trained to retain and / or obtain at least some of the coordination may lead to both physiological and psychological improvements for the patient. For patients having a head injury, the training may be divided into two sections since the patient may have lost control over tat least one of the eyes. The first section would then be to train the muscles around the eye the patient cannot control so that the patient may obtain some control over that eye. The second section is to establish and / or improve the coordination of at least one of the eyes. This may include establishing and / or improving binocular vision.

[0085] The aspects of the invention may be used for treatment of patients suffering from stroke-related brain disorders. A stroke may lead to loss of coordination of at least one of the eyes, which may lead to a visual disorder. Rehabilitation where the eyes get trained to retain at least some of the coordination may lead to both physiological and psychological improvements of stroke patients. For patients that have suffered from a stroke, the treatment and / or rehabilitation may include the two sections that are set out above

[0086] The treatment may be via a direct treatment effect of the exercise. Treatment may be via an indirect treatment effect of the exercise, i.e. the visual impairment treatment facilitates a traditional treatment of the disease that is otherwise interfered with or affected by untreated visual impairments.

[0087] Some stroke patients experience visual disturbances that affect stereo vision. The type of co-vision training / treatment that we can perform in our device is expected to have a positive impact in the rehabilitation of this group of stroke patients. The inventors have realized that its use can be expected to have an unexpected positive impact in the treatment of stroke patients.

[0088] In stroke patients, training of stereo vision can take place. Stereo vision may have been present in this patient before the stroke occurred. The prospects for an effect of the training on the treatment of stroke-related conditions are very good. The prospects of recovering stereo vision with the training are very good. Restoration of parts of the visual field may be facilitated by the training.

[0089] The recoveries can be speculated to be due to the creation or recreation of neuron connections or neuron function in the treated patient's brain.

[0090] Unpleasant double vision can be treated.

[0091] The healing process can be accelerated with training.Self-healing can be accelerated or made possible.

[0092] Thus, in addition to restoration of stereo vision, the healing process of the effects of the stroke itself may be unexpectedly accelerated.

[0093] It has been shown that the image manipulations used in the devices and methods described herein can also have an unexpected impact on conditions other than those described above.

[0094] These conditions may be related to various brain dysfunctions or related disorders including psychical health such as, depression, high sensitivity (such as hypersensitivity), sleep deprivation etc. The sensitivity may be related to pain and / or sensory experience, such as touch, sound, visual etc.

[0095] The reason is that when the brain has to work to compensate for an issue with eye coordination, the brain will be burdened which means that it may have harder to compensate for other issues. When establishing and / or improving the eye coordination, they brain can focus on handling problems which may then reduce the impact of these for the patient.

[0096] Embodiments provide in particular for treatment of amblyopia, amongst other binocular vision disorders described herein.

[0097] The visual impression of an object detected by the eyes becomes decoded in the visual cortex in the back of the brain. The information gets processed in the visual cortex and for an observer having normal binocular vision superimposed information gets revealed, e.g. depth perception. For most observers having a binocular eye disorder this additional information does not fully develop, depending on the type of eye disorder and degree of severity of the same. For an observer having e.g. an amblyopic eye, otherwise known as lazy eye, decodes most of the visual impression from the other eye and consequently fails to benefit from additional binocular information. A strabismus observer will experience a similar situation.

[0098] Phoria problems are common complaints among patients in practice. They can present a history of tiredness when reading, asthenopia, diplopia (double vision) during near point tasks or trouble focusing from near to far. There can be various conditions limiting the ability to converge, such as changed vision demands, psychological factors and psychopharmacological drugs, under function of the extra ocular muscles or in more rare cases the cause is neurological. Convergence insufficiency, is the most common type of decompensated phoria, and can mainly be found in patients with exophoria, but even esophoria, at near, though this is rare. The most common is an exophoric condition. Orthoptic therapy improves the near point of convergence (NPC) and the fusional vergence ability, i.e. the ability to control the phoria.

[0099] The components of the ocular-motor system, accommodation and vergence eye movements, are responsible for providing clear and single vision. Fig. 1 illustrates a person having a left eye 12 and a right eye 14. The horopter 13, and Panum's fusional space, 10 within which all objects are seen singly. Double vision, diplopia, occurs for objects outside the boarders of Panum's fusional space (11 and 15), as illustrated by the dual objects outside the Panum's fusional space in respect to the single objects within the same. When having convergence problems, the person isshowing a remote near point of convergence (NPC). NPC is the nearest point where the patient reports that the target has become double or the examiner observes one eye losing fixation and turn outward / inward, whichever occurs first. NPC is conventionally measured with a RAF-ruler. Normal values of NPC range between 4 cm and 16 cm from the corneal plane. Values greater than 16 cm, which is to be considered as a reduced ability to converge, may give symptoms in near vision.

[0100] However, in some studies it is considered desirable to be within the 10 cm limit. An observer having normal binocular vision who wishes to change fixation from a distant object to one near (or vice versa), then the retinal image of the target object is initially defocused (blur describes this error of focus) and there is a fixation error between the image of the target and the fovea (disparity refers to this error of fixation). In order to bring clarity to the retinal image the eye must focus in a process known as accommodation, and to overcome disparity the eyes must change vergence angle to maintain fixation within corresponding retinal areas (if non-corresponding points of the retina stimulated then double vision will result). In Fig 1 the desired fixation point, 18a, for an observer having no eye disorder is seen as well as fixation point, 18b, of an observer having an eye disorder, thus showing an exophoric fixation disparity. Fixation disparity is a condition in which the visual axis does not intersect at the object of regard but that the object is still imaged within Panum's fusional space. Commonly the dominant eye is directed towards the object of regard, and the fellow eye is directed slightly more convergent (in esophoric conditions giving rise to esophorix fixation disparity) or divergent (in exophoric conditions giving rise to exophoric fixation disparity). When fixation disparity occurs a person with compensated phorias will act upon the disparity to place the image of the object on corresponding retinal point, i.e., the disparity will be eliminated. Fixation disparity then serves as a cue to the final convergence or divergence movements of the eyes

[0101] Accommodation is an involuntary adjustment of the eye to focus the image of an object on the retina. In accommodation for near vision, the ciliary muscle contracts to reduce tension on the lens and allow it to become steeper, that is, to become more convex. Several factors reduce the accommodative mechanism. During the normal aging process the lens becomes stiffer.

[0102] Environmental, genetic and other factors can increase lens stiffness or weaken the ciliary muscle. These result in headaches and discomfort when working on near tasks such as reading or focusing on a computer screen.

[0103] Binocular fixation of a stationary object requires that both visual axes are aligned with an object of interest in order to eliminate double vision, see Fig. 2 middle (e.g. no strabismus).

[0104] Examination of the muscular and neurological systems involved in the coordination of the two eyes can be carried out using a cover test. The cover test consists of the covering and uncovering of each eye in turn while the fellow eye maintains fixation on a target. If no movement is seen of in either eye when the other eye is being covered demonstrates a phoria. In the case of a phoria the eye behind the cover will move either inwards (i.e., an esophoria is present, see Fig. 2 bottom left) or outwards (i.e., an exophoria is present, see Fig. 2 bottom right). Any movement of the eye when its fellow is beingcovered indicates the presence of heterotropia (commonly referred to as strabismus or squint), as seen in Fig. 2 top. Strabismus can either be convergent (esotropia) or divergent (exotropia) and can affect either eye, as illustrated in Fig 2 top. For the purpose of illustration Fig 2 top left shows a left esotropia and top right shows a left extropia. The primary sensory effect of strabismus is amblyopia in the non-fixating eye. One of the consequences of amblyopia is an increased threshold for stereopsis. Strabismus can result from adaptive pressures being placed on a compromised binocular system.

[0105] As mentioned in the background section, the treatment of strabismus is aimed at: 1) eliminating suppression and amblyopia; and 2) realigning the eyes to restore binocular perception. Embodiments provide either for the first, the second or both of these treatments.

[0106] Conventionally, surgical treatment of strabismus is an intervention where the eye is repositioned in the eye socket in a way to achieve aligned visual axes. However, by relocating the eye bulb in a sense chance the retina's position in relation to the observed object. Hence, will the impression of vision be miss-aligned in the visual cortex which may result in a loss of binocular vision, i.e. double vision. For some individuals the strabismus will re-establish itself over time due to the visual cortex is trying to align the visual impressions from both eyes and by doing so the visual axis of the previous affected eye is change back, i.e. the visual information of the retinal image corresponds between both eyes again.

[0107] There are two groups of methods used for treatment of amblyopia in strabismus and for non-surgical treatment of strabismus: occlusion methods and those using a biofeedback procedure. Until recently the most effective method for treatment of strabismic amblyopia was occlusion. This method is based on the occlusion of the dominant eye by patching and thereby forcing the crossed eye to perform the visual function. However, this method does not provide for a control of the ongoing therapy. With one patched eye, binocular vision is not possible, and it is doubtful if an efficient training can be achieved by this conventional method, as already mentioned in the afore background section.

[0108] The biofeedback therapy method is a technique which is based on conditioning principles and has been used in a variety of applications. The technique provides a person with immediate information from the biological process which normally is beyond his conscious awareness, thus facilitating voluntary regulation of these same functions. The methods for vision correction based on a biofeedback procedure can be divided into two categories. The first method is targeted on the improvement of visual acuity of the eye with a misaligned optical axis. The methods falling in the second category use autotraining to develop endogenic reflectory mechanism in order to reduce the degree of optical axis misalignment in the crossed eye. Embodiments described below may be based on each of these two methods.

[0109] Methods for treatment of miss-alignment of visual axis are disclosed in US 6,033,073. The visual training system disclosed comprises image viewing means, wherein the patient is hooked up to the training system both with electrooculogram electrodes and with electromyogram electrodes. During a session series of images are displayed and responses are measured via the different electrodes andanalyzed to assess differences between the eyes. However, this visual training system is hardly suited for children due to the number of electrodes used to get reliable results and the fact that children most often lose interest in training. Moreover, the system is not suited for home training based on the high level of experience demanded of a person applying electrodes to a third individual to get accurate results of the monitoring. At hospitals and / or neurophysiology departments these people are highly specialized trained nurses. This directs use of the visual training system disclosed in US 6,033,073 not to be used at home because of potentially not reliable measurements.

[0110] For training peopple affected by decompensated phoria or strabismus with suppression and amblyopia, one way of doing so could be to use a mask for at least partially block and / or blur a portion of the media presented to at least one of the eyes. In some examples, the mask used for each of the eyes are different, such as what is blocked and / or blurred for one eye is not blocked and / or blurred or the other eye and vice versa. The vision parameters may then be manipulated for each of the eyes, such as manipulating the mask and / or manipulating other vision parameters. This may include manipulation of the presented visualization, such as moving the mask and / or moving the image behind the mask. It should also include manipulating the area being masked.

[0111] However, it will be appreciated that the invention is not limited to this application but may in embodiments be applied to various other binocular vision disorders suitable for orthoptic treatment.

[0112] Embodiments target on training the visual cortex in order to achieve an evenly matched eye vision processed by the visual cortex: By showing images or visual presentations within the Panum's fusional space, i.e., with a slight variation in disparity, vergence eye movements are introduced to the person not being aware of the induced variation and the persons vergence capability will increase; and with unequal intensity for the two eyes presentation suppression and amblyopia can be treated in embodiments by means of forcing the person to use the suppressed or amblyopic eye. By image manipulation, as presented below, a unique situation is provided for individuals with an eye disorder as each eye is provided with a unique image to interpret in the visual cortex. As respectively of the two eyes are presented with a unique image, and thus the brain, i.e. the visual cortex, becomes involved to align the visual impression from each eye to obtain an aggregated comprehensive understanding. By changing and / or manipulating different image parameters or vision parameters differently for each eye, a unique situation is provided where the patient is enabled to exercise the visual cortex, and in some extent even the ocular muscles involved. However, exercise in the present context should not be confused with purephysical training of muscles. For situations where both sensational and motoric capabilities are to be coordinated by an individual to achieve a new, higher or elevated skill or ability, perceptual motor learning is commonly used as a comprehensive concept.

[0113] An embodiment of the invention will be described according to a system or apparatus 30 shown in Fig. 3. However, to substantiate the fundamental principle of the invention is not confined to this embodiment of a system configuration for visualization.The system, 30 comprises a first screen 32 and a second screen 34 with a semi-transparent mirror 36. The system 30 also has a processing unit 39, and a blocking device 35 in relation to a person or patient 31 , and an input device 33 and optionally or additionally the system 30 comprises an eye tracking device 38. The embodied system 30 is thus computer based and may be adapted to perform certain methods of perceptual motor learning.

[0114] The apparatus or visualization system is divided into a right hand-side part and a left handside part in respect to which vision field is affected, such as illustrated in Fig. 5. The processing unit 39 controls the visual presentations based on image data on the first screen 32 and the second screen 34. Each screen in this embodiment is covered with a polarized surface layer, exposing the images to the left and the right eye with the aid of the 50 % reflective mirror 36. The blocking device 35 facilitates separation of visual presentations from the dual set of screens, i.e. blocking a visual presentation based on image data from either visual field to be visible by the not intended eye.

[0115] The separation of visual information from the visual presentations is further illustrated in Fig.

[0116] 5 where the separation into a right hand-side part and a left hand-side part is illustrated. The visual information from the first screen 32, illustrated by dotted line in Fig. 5, is reflected and diverted by the mirror 36 towards the patient's right eye 12 via the blocking device 35. The patient's left eye 14 simultaneously registers visual information from the second screen 34, illustrated by dashed line in Fig. 5, which is passing through the mirror 36 and the blocking device 35.

[0117] Moreover, the processing unit 39 is arranged to provide a predetermined visual effect beneficial for the treatment of the person suffering from an eye disorder, comprising a binocular vision disorder to be treated. In some embodiments of the apparatus the visual presentation based on image data in first and second visual fields is provided to oscillate with an asymmetrical fluctuation in relation to each other to exercise the perceptual motor learning. The two image units or monitors and a mirror implement the principle of physiological diplopia to induce convergence in creating a computerized stereogram. This is the basis that it can be adapted to different types of visual defects by the software. This adds range and variety to NPC exercises thus provided.

[0118] The first screen 32 and the second screen 34, display, monitor or image unit represent physical units to divide a visual presentation based on image data into a first visual field and a second visual field. The first visual field is e.g. aligned with the right eye 12 and the second is aligned with the left eye 14. However, some embodiments may utilize a single display unit to archieve such a separation of images into a first visual field and a second visual field. For these embodiments, such as 3-D screens having a single 3-D display, the reflective mirror may be omitted.

[0119] The apparatus 30 provides establishing and / or improving binocular vision by perceptual motor learning for the adaptation of the visual system of a patient suffering of a binocular vision disorder. The apparatus has a set of two units, i.e. the first screen 32 and the second screen 34 - one for respectively eye, for manipulation of a vision parameter of the visual presentation, e.g. a picture, movie, or image. To control the visual presentation on respectively unit, the processing unit 39 isoperatively connected thereto. The processing unit 39 is adapted to provide or determine a boundary value of at least one of a first vision parameter and a second vision parameter for the first and / or second manipulation of the first and second unit. The boundary value is the value of the at vision parameter where binocular vision disappears for the patient. Alternatively, a plurality of vision parameters may be modified to determine a multi dimensional field of these values which has a boundary border within which binocular vision is present and outside of which binocular vision is distorted. In the latter case, the boundary value is the aforementioned boundary border of the multi dimensional field. Furthermore, the processing unit 39 is adapted to control at least one of the vision parameters by oscillated or fluctuated manipulation within a first range on the first and / or second unit. The first range has an extreme value, such as maximum value that is less than the boundary value, for the perceptual motor learning. This means that at least one vision parameter is actively changed, but kept in the first range, during a therapy session for at least one of the visual presentations. The vision parameter is changed to keep the patient vision within the Panum's fusional space. This means by showing images or visual presentations that are kept within the Panum's fusional space, the therapy is advantageously provideable by the present apparatuses and methods. This manipulation is described in more detail below.

[0120] Alternatively, and / or additionally, the first screen 32 and the second screen 34 could each comprise at least one vision parameter to be manipulated. During a training session only one of these at least one vision parameter may be manipulated (including oscillated or fluctuated) e.g. spatially for each screen respectively. The other vision parameters will be kept constant.

[0121] To create a more challenging environment for the eyes during a training session, more than one of the at least one vision parameters could be varied or adjusted simultaneously e.g. to fade out the image for the dominant eye; or to fluctuate the fading, e.g. for the dominant eye, within a set range, determined by a boundary value. The manipulation of further vision parameters will overlap with e.g. spatial manipulation (i.e. fluctuation or oscillation) of at least a part of the images presented on the first screen 32 and the second screen 34.

[0122] As an alternative, the first unit and the second unit may be part of any of a virtual reality (VR) headset, an augmented reality (AR) set, a mixed reality (MR) set, and an extended reality (XR) set.

[0123] It has been shown that VR is particular good for treatment of amblyopy since it will provide a dark surrounding.

[0124] As seen in Fig. 4 the size of the first visual presentation 40 based on image data may be a proportion of the screen size 44 of the first display 32. The same applies to the second visual presentation, namely that the size of the second visual presentation based on image data may be a proportion of the screen size of the second display 34. Usually, the relation between physical screen size and size of the image displayed thereon is opposite, i.e. a proportion of the screen size occupied by the displayed image is less than the size of the larger screen. A superimposed common imagecomprises the images from both the first display unit 32 and the second display unit 34 via the semitransparent mirror 36.

[0125] Some embodiments utilize smaller screen units, such as wearable glasses with individual displays, such as miniature monitors or screens, for each eye to achieve the superimposed common image that is to be perceived by the patient. Each display for these embodiments is in close proximity with respective eye and directed specifically towards the same, thus no mirror is needed, and the image is superimposed in the visual cortex of the person wearing the glasses. The individual visual impression from each eye is processed by the brain. For these embodiments the blocking device may be omitted as individual information is presented to each eye.

[0126] Alternatively, the first unit and the second unit may be part of any of a virtual reality (VR) headset, an augmented reality (AR) set, a mixed reality (MR) set, and an extended reality (XR) set The patient 31 is positioned in front of the set-up and focuses on the superimposed common image on the mirror 36. This focus on the common image is done unconsciously by the patient. The superimposed common image is perceived by the person on a virtual 2-D surface, moreover, this 2-D surface is perpendicular to the vision axis of the person.

[0127] The first and second display 32, 34 may show a first image and a second image either as identical images of which for instance only the spatial position is modified during a training session.

[0128] Alternatively, or in addition, the image contents of the first image and the second image may differ.

[0129] For instance, the visual presentation may be a stereoscopic image presentation that relies on the presentation of a slightly different first image and second image to each eye. A stereoscopic image presentation is based on a pair of 2-D images, namely the first image and the second image representing two perspectives of the same object, with a minor deviation similar to the perspectives that both eyes naturally receive in binocular vision. In this manner, a 3-D illusion may be created for patients having established or improved binocular vision starting from the pair of 2-D images, whereby depth perception is created in the brain based on the two images or the superimposed image. Hence, embodiments may take advantage of such 3-D images, but it is not necessary for all embodiments. In the present embodiment, the two images are presentable as a computerized stereogram, wherein the individual images are separated, e.g. by means of blocking device 35, such as glasses with differently polarized lenses, see Fig. 5.

[0130] At least a portion of the first image and the second image, or the superimposed image, may be a series of single image frames, such as a movie, or a computer program application, such as a text processing program or a spreadsheet program.

[0131] In order to initially calibrate the visual system to the patient, the patient is allowed to act on an input device 33. The boundary value is thus determined. Alternatively, an initial boundary value may be determined previously, e.g. by an optician, and provided as an initial boundary value.For some training, only values provided by a practitioner, such as an optician or a doctor, is used. The training could be performed in steps where the practitioner has provided a training subscription starting at one boundary value and then successively changing the boundary value for each training session or after a set number of sessions, making the training more and more challenging until the eye coordination has been established and / or improver, for example when binocular vision has been obtained.

[0132] For determining the boundary value, the input device 33 is arranged to register user input, for instance such as e.g. a button, joystick, microphone or any arbitrary input device. The patient may also provide a movement, such as a gesture, with a body part, such as a nod with the head or moving an arm. The input device 33 is used to register a response from the patient when the patient starts to experience a distorted vision, such as when the presented superimposed image as perceived as distorted. The input could for example be performed by pushing a button or by a sensor registering a specific eye movement made by the patient or using the eye tracker. The input could also be a movement of a body part, such as a gesture including a nod with the head, moving an arm, a hand, a leg etc. This distortion is provided by manipulating at least one vision parameter for first and / or second visual presentation shown to the patient. For instance, the first and second images are moved in opposite spatial directions, their size is changed individually, their sharpness is blurred, etc. When the patient loses binocular vision, i.e. sees double objects, the patient input is registered and thus the aforementioned boundary value is determined.

[0133] The image in the first and second visual field is for instance slightly separated from each other over a short period of time, as the image emerges on the superimposed common image. At a certain level of displacement of the images, depending on the individual and the severity of the eye disorder, the patient begins to lose binocular vision, i.e. sees double objects. The spatial displacement of the image is performed in this embodiment in two directions. To determine the extreme displacement values, such as a minimum value and a maximum value, , the right hand-side-part image is displaced even further to the right vice versa for the left hand-side-part image. The minimum displacement value the right hand-side-part image is displaced to the left, in some sessions even beyond the left hand-side-part image vice versa for the left hand-side-part image. To properly define the boundaries for single vision, the calculation procedure may be repeated until satisfactory measurements are obtained. A mean value of several boundary values may thus be determined as the boundary value used in the subsequent procedure.

[0134] Thus, at this stage the interval of the Panum's fusional space 10 is determined by the apparatus 30 within the person specific boundaries, as now defined by the data of the boundary value available for further use in the system. This is illustrated in Fig. 1, at limit 11 and limit 15. From this value determined for the specific person, a therapy session boundary value is defined. The determination of a current boundary value may be repeated during a therapy session. This provides for an up-to date tuning of the therapy based on current determined values of the specific patient. Inthis manner, the therapy session takes the patient's situation and condition into consideration, e.g. by lowering the boundary value when the patient becomes tired. Alternatively, or in addition, the therapy session may be automatically ended, when the boundary value is below a predetermined minimum value, i.e. when double vision occurs too quickly or early. In this case, the patient may continue to play the visually presented computer game or continue watching a movie, however with the manipulation of the vision parameter(s) disabled.

[0135] Then exercises are performed based on this boundary value. Training is made based on a specific proportional share of the boundary value of the person's capacity, i.e. a vision parameter is manipulated to a lesser degree than the boundary value, such that binocular vision is maintained during the training session as the Panum's fusional space 10 is not left. For instance, vision parameters are manipulated up to a value of approximately 70% of the determined boundary value. The specific ratio may be individually adapted in order to prevent fatigue or to avoid that the individual loose interest in doing the exercise, due to the task may be too demanding.

[0136] A ratio value between the maximum value of the first range value and the boundary value is in the interval from 0 to 1, preferably in the interval 0.6 to 0.95. The ratio value has a maximum value where efficiency of the perceptual motor learning for the patient does not occur or where efficiency of the perceptual motor learning for the patient is undetectable.

[0137] Additionally, or alternatively, as already mentioned, the first initial value for the boundary value could be based on and provided by an eye doctor or responsible therapist. The initial boundary value could also be determined through measurements performed by an eye doctor or responsible therapist. The boundary value could thereafter be individually determined and subsequently updated during the training session. The update may be based on input from the patient or the patient's treatment history or measurements performed during the training session. The updates of the boundary value could be controlled to follow the patient's development or the patient's treatment history. An individually adapted boundary value is used in order to prevent fatigue or to avoid that the individual loses interest in doing the exercise.

[0138] The longer a training session lasts, the more tired the patient gets and it is therefore provided to adjust the first range in dependence of the training time, e.g. descending the first range over time, to compensate for fatigue or tiredness.

[0139] Some embodiments include an eye tracker 38 for both the right hand-side part and a left hand-side part of the visual system. The tracker and the display are linked to each other such that the information from eye tracker yields information regarding the amount of displacement of the image on the display. The processing unit may thus be adapted to assess the information from the eye tracker and divert the output to the corresponding display. In some embodiments an eye-tracking functionality asses a potential amount of strabismus of the patient as an input concerning the progress of the vision therapy. Based on this spatial information the image of the display, which corresponds to the eye with the miss-aligned visual axis, may be changed to counter-act the miss-alignment.Separating the two individual images on the superimposed common image based on the individual visual presentations of the first and second display unit 32, 34 further apart stimulates increased convergence. Moving the two individual images closer makes convergence easier.

[0140] The processing unit 39 puts variation to this superimposed common image by manipulating the visual presentations based on image data, i.e. pictures, images, etc. For instance, a back and forth relative motion of the images, i.e. the individual visual presentations of the first and second display unit 32, 34, is performed. The range of movement is kept within the above portion of the boundary value, so that binocular vision is maintained, but varied. In this manner the eyes are trained to converge and diverge during the therapy session. This superimposed fluctuation of the image in the first and second visual field displaces the image slightly within respectively display around a predefined separation level where the two images are no longer on the same screen position of the virtual screen where the superimposed common image is shown. To which degree the image will oscillate is set by the calibration made by the patient, and the maximum range being a portion of the boundary value, as explained above. This enables the exercises to follow the person's progress in the therapy in both directions. If the person is tired, has less concentration, or is weak one day, the processing unit puts the requirements on a lower level, and vice versa. The processing unit is following the advancement when the patient condition improves, and binocular vision capability is getting stronger and stronger.

[0141] In addition, the displacement of the image for each visual field, i.e. the first and second field, may be chosen to be below a predefined distance amplitude, i.e. a maximum distance value, as to secure the image does not get distorted by truncation due to e.g. physical dimensions of the first and second display or the physical dimension of the mirror. Otherwise, the efficiency and relevance of the eye training may get diminished due to the fact that the patient's visual cortex will process information of the two individual images not fully aligned with each other (Panum's fusional space 10 would be left).

[0142] In other embodiments, other physical circumstances may alternatively and / or in addition be of relevance to restraining the manipulation of the images depending on the parameter to manipulated. The spatial displacement of the image on each of the image units 32, 34 is controlled by the processing unit 39 by manipulating the image based on a function of time. This manipulation function may in some embodiments of the invention be a continuous reciprocating function, e.g. a sinusoidal function as shown in Fig. 6. Alternatively, the fluctuation function may be a discontinuous reciprocating or stepwise function, e.g. as shown in Fig.7. Other waveforms for the fluctuation functions are possible e.g. square, triangle and sawtooth or any combination thereof or even irregular periodic waveforms. The functions shown in Fig. 6 and Fig. 7 are part of the prior art, in the present disclosure, these types of functions may be used as a first oscillating base component.

[0143] In addition, pause times may be provided between series of manipulation. Pause times may provide for a recovery of a tired patient in terms of binocular vision. Thus, extended therapy sessions may be provided compared to sessions where perceptual motor learning is performed continuously.The time period for the function is beneficially more than 1 second, i.e. a frequency below 1 Hz, for the reciprocating function. Examples for suitable frequencies, with being limited to these specific frequencies, are for instance in the range from 0,1 to 0,9 Hz, such as 0,1 ; 0,2; 0,3; 0,4; 0,5; 0,6; 0,7; 0,8; or 0,9 Hz. With shorter time periods the demands on the individual suffering from an eye disorder may become too large, which might lead to undesired or ineffective perceptual motor learning.

[0144] As seen in Figs. 6 and 7, the image in the first visual field A fluctuates following function 60, while the image in the second visual field B follows function 62, respectively 70 and 72. The fluctuating curve function applies in particular to the spatial position of the respective image. Either of the parameter's amplitude, frequency and the overlap of the functions may in some embodiments be predefined by the ophtamologist and / or the health provider. For the discontinuous fluctuation function the step size and duration of each step may also be predefined by the orthoptist and / or the health provider. A fully interactive visual apparatus may in some embodiments fully adapt these parameters to match the need and demands of the patient's eye disorder to fully achieve adequate and efficient eye training and exercise session.

[0145] The fluctuation function may be applied to various vision parameters, singly or in combination, to provide the perceptual motor learning. Preferably, the fluctuation is first, or only, applied to the spatial parameter. In addition to that other parameters may be modified accordingly.

[0146] The processing unit performs different types of tasks depending on the requests of the session, such as pictures, movies and computer games or any other arbitrary images displayable by electronic means. The movies and games are interesting for themselves for the patient, and the images, pictures, or movies may have an interactive audio component to them. A voice asks for instance a couple of simple questions about the picture, in order to provide that the patient does not lose concentration or focus from the visual presentation during the therapy session. The patient may thus provide a valuable feedback that the exercise is efficiently followed during the session. This data may be saved for later use.

[0147] The processing unit 39 further incorporates the capability to intermittently store patient related data concerning the individual's specifications as treatment settings and also for the ongoing training session. Such patient related data may comprise patient performance data including a value on the displacement where the individual lose binocular vision, and therapy session data, including specifications thereof as e.g. start time, duration of the session, number of calibrations performed, what type of exercise, movie, game, picture and so on. All stored data is logged with a time indication and available for further processing or action.

[0148] Prior to start of the exercise and training session the individual have to identify him / her-self to the computerized image manipulation apparatus. This identification may for instance be performed by either a hardware token e.g. an usb-stick, smart card, or a software token e.g. an individual code entered to the apparatus using a keypad or keyboard, and / or by using biometric data, e.g. fingerprint,retina recognition etcetera. When the individual is properly identified, the specific settings are loaded into the processing unit that controls the image manipulation. The computerized image manipulation apparatus is now attuned to the needs and demands of the individual commencing the session.

[0149] Moreover, the processing unit 39 may has communication ability for down / up-loading specification and stored information to a centralized common database. The centralized common database is preferably reachable via the internet using TCP / IP. When, as described above, the individual logs into the apparatus, a communication channel opens to the centralized common database and checks and / or retrieves settings for the individual. If new information and settings are to be updated these are downloaded and loaded into the processing unit that controls the image manipulation. After the exercise and training session is completed the gathered performance data, e.g. intermittently stored on the processing unit 39 or in another memory of the apparatus 30 (not shown) during the therapy session, is uploaded to the centralized common database. The communication ability for down / up-loading provides for e.g. the health provider to interactively communicate with the patient and / or to post a message to the patient. The message will be displayed during the next session or sessions initiated by the patient.

[0150] The centralized common database facilitates base data and supporting evidence to be analyzed in respect of further develop the computerized image manipulation apparatus by e.g. changing initial settings depending of the status of the eye disorder for a population. For instance, compliance of the patient to the prescription can be more easily monitored remotely using the centralized common database by checking specific data, which is cost effective and potentially more reliable the e.g. an interview of the patient. Furthermore, by the centralized common database each computerized image manipulation apparatus is tracked and surveyed in order to e.g. avoid breakdowns or detect any potential faults. Updating the computerized image manipulation apparatus may also be possible by utilizing the information in the centralized common database.

[0151] An example of an image is shown in Fig 8a and Fig. 8b where in Fig 8a an example of the image for the first screen 32 is shown, which e.g. is directed for perception by the right eye. In Fig 8b an example of an image is shown for the second screen 34, which e.g. is directed towards the left eye. By superimposing the first and the second visual field to a single visual field, an image is shown as illustrated in Fig 9a, the common superimposed image 92. This common superimposed image 92 may be split into the individual images for each eye by means of using the blocking device 35, whereby a separation of the visual fields is maintained, as illustrated in Fig. 9b. The effect of the blocking device 35 for the left eye respectively the right eye, is illustrated in the circular sectors in the lower corner of Fig. 9b at respectively side thereof. Thus the right and left eye of the patient will only receive the expected image as the non-intended image is blocked to enter respectively eye, i.e. retina.

[0152] Alternatively, individual visual presentations may be provided to each eye, e.g. by the aforementioned glasses with miniature screens, whereby the blocking device may be omitted. The indications R and L in Fig. 8a, 8b, 9a and 9b are for illustrative purposes only, and indicate the first and the second screen,respectively, i.e. the right and left screen in the example. The indicators are part of the image contents and are neither shown nor necessary for the actual implementation of the embodiment herein discussed. The image contents of images or visual information present therein is irrelevant in embodiments. However, specific image contents of images may allow for easy identification of objects, be undemanding or non-straining and thus easy to watch, easy to focus on, etc., which might be convenient in some cases.

[0153] While the initial settings are determined for a degree of strabismus and / or a degree of amblyopia, training can effectively be performed and the variation of the vision parameters is performed. For instance, on the display which corresponds to the dominant eye, i.e. non-amblyoptic eye, the image is changed back and forth between a sharp clear image and a slightly blurred, i.e. a vague or less distinct, image. This small continuously change of sharpness diverts the visual cortex to assess more of the image from the retinal image of the amblyoptic eye. Over a time period with daily sessions of training, the visual cortex will equate the image processed between the eyes. As a result of this perceptual motor training, the patient will gradually get additional or improved visual perception as e.g. depth perception. Several other image and / or vision parameters may be used in this respect for suitable manipulation by image processing e.g. the color information, fading the color image back and forth between full color and a grayscale image. Alternatively or in addition, the manipulation may comprise to manipulate vision parameters, such as a specific color component in the presented image. Alternatively or in addition, at least a portion of one of the presented images may be actively faded out either in respect to the other image, or by changing the intensity on either image in respect to the other. Alternatively or in addition, either image may be blurred or modified in terms of sharpness in respect to the other image, to mention a few options.

[0154] Some embodiments may manipulate different vision parameters in respect to respectively eye, while other embodiments use and manipulate the same vision parameter for both eyes.

[0155] Alternatively or in addition, only the vision parameter for one of the eyes is manipulated to achieve the result of perceptual motor training.

[0156] Image processing may comprise manipulation of vision parameters of visual presentations, e.g. based on image data, such as spatial parameters including dimension or position of an image, or purely vision parameters, such as defocus, fading, color change, intensity, and / or illumination. Image processing in this context also comprises movement, displacement, rotation, position, size and other types of spatial operation of the image on the screens. For these parameters the threshold value, as discussed above, reflects the physical limitation for the particular parameter chosen in regard to the specification of the equipment for that parameter. To restrain the parameter within the specification boundaries the efficiency of the exercise is maintained as the image is not truncated in a way that it disturbs the visual system of the patient.

[0157] Moreover, to establish and / or improve binocular vision a method is provided using the above described apparatus, for providing perceptual motor learning for the visual system of a patient havinga binocular vision disorder. The method comprises manipulating at least one first and second vision parameter related to a visual presentation directed towards to each eye, respectively. By determining a boundary value of a vision parameter for the manipulation, where binocular vision disappears for the patient, a manipulating, including oscillating or fluctuating, of the vision parameter is controlled within a first range below the boundary value. Furthermore, the first range having a maximum value that is less than the boundary value, the perceptual motor learning is effective without unnecessarily tiring the patient during a therapy session.

[0158] The described examples may be at least partly implemented by means of a computer program. The computer program may be provided to enable carrying out some steps of the method of perceptual motor learning according to the above. A computer-readable medium having embodied thereon the computer program for processing by a computer for establishing and / or improving binocular vision is provided. The computer program comprises a plurality of code segments for a first and a second manipulation of at least one vision parameter for respectively manipulation, related to a visual presentation directed towards each eye, respectively. Code segments may be provided for facilitating determining a boundary value of the vision parameter for the first and / or second manipulation, where binocular vision disappears for the patient. A range of manipulating vision parameters may for instance automatically be increased during determination until patient input is made at the boundary value. Alternatively, the boundary value may be determined previously and provided, e.g. in a memory, to a code segment of the computer program for processing. Further, code segments are provided for controlling the manipulation, including oscillating or fluctuating, of first and / or second vision parameter within a first range, where the first range having a maximum value that is less than the boundary value, for the perceptual motor learning.

[0159] While the brain and the individual have experienced the additional image, the next process is to attend to the heterotropic eye, the miss-alignment of the visual axis. On the display which corresponds to the miss-aligned eye the imaged is spatially changed back and forth towards the direction for an individual having two parallel visual axes. The small change of the image on the two-dimensional display affects the visual cortex processing the presented visual presentation or image as to intermittently lose e.g. depth perception. As the individual has previously experienced the additional image the brain is trying to regain the lost information. And as the changes are minute and the ocularmotor system engages the eye muscles to effectively counteract the loss and regain the information. A sequence of superimposed common images is shown in Fig. 10 a-h. Images from the first and second visual field are aggregated and slightly displaced in respect to each other, wherein the smallest distance is shown in Fig 10a and the largest in Fig. 10h. The effect of the blocking device 35 is less visualized as in the earlier part for this sequence example, due to illustrative limitations. Over a period of time the displacement of the image on the display corresponding to the heterotropic eye will be less pronounced. This will however be a gradual change as it is necessary to perform the eye training on the verge between fully visual perception and slightly losing the same. The indications R and L in Fig.10 a-h are for illustrative purposes only, they are neither shown nor necessary for the actual implementation of the embodiment herein discussed.

[0160] Fig. 11 illustrates the concept of asymmetrically fluctuated oscillation. The image shows an arbitrary unit for providing the first unit A and second unit B, each unit configured for presenting at least a first and / or second vision parameter.

[0161] The asymmetrically fluctuated oscillation prevents the visual system from adapting to a repetitive stimulus pattern, thereby maintaining perceptual challenge during training.

[0162] In some examples, an asymmetrically fluctuated oscillation is obtained by applying an irregular modulation to a base oscillation, such that at least one of amplitude, frequency, or offset of the base oscillation varies over time. An asymmetrically fluctuated oscillation may thereby exhibit irregular fluctuation, such that successive oscillation cycles are not mirror-symmetric or temporally repetitive. However, an asymmetrically fluctuated oscillation is not limited to oscillations obtained by irregular modulation, and may be achieved by any oscillatory manipulation that results in non-symmetric fluctuation. The non-symmetric fluctuation may be temporal, spatial, or a combination thereof. For example, asymmetrical fluctuation may also be achieved by deterministic modulation schemes that result in non-mirror-symmetric oscillation.

[0163] In Fig. 11, a schematic asymmetrically fluctuated oscillation is illustrated for manipulation of the first vision parameter on the first unit A. The asymmetrically fluctuated oscillation oscillates around axis 0L. AS a manipulation of the second vision parameter on the second unit B a schematic oscillation is illustrated which oscillates around axis OR.

[0164] The asymmetrically fluctuated oscillation includes a first oscillating base component and a second random or noise component. The second random or noise component is added to, or superimposed on, the first oscillating base component. The first oscillating base component includes a continuous reciprocating function, such as a sinusoidal function, a square function, triangle function or a sawtooth function; this could be a function as described in relation to Figs. 6 and 7. The schematic function illustrated to manipulate the second vision parameter on the second unit B is, in the illustrated schematic example, the first base function of the asymmetrically fluctuated oscillation for manipulation of the first vision parameter on the first unit A.

[0165] The asymmetrical fluctuation element of the oscillating movement is provided by a second random component including at least variations in one of a frequency f, an amplitude Amp and an offset 0 of the first base function. The random component may randomly change at least one of the parameters either positively or negatively to challenging the brain during the training. Preferably, for binocular vision training, binocular vision should be maintained during any change of the parameters. The random component could be controlled using different methods. One way could be to change the weighting so that when the image is moving towards an extreme value, such as a boundary, minimum, or a maximum value, the probability that the direction changes is increased the closer to the extreme the image moves. A change of direction may be done by changing the sign of the variation of the offset0 and / or amplitude amp. Alternatively, and / or additionally, when the frequence f is varied as part of obtaining an asymmetrical fluctuation of the oscillation, the frequency f may increase, the more the frequence f increases the higher may the probability be that the frequency f may decrease, and the other way around.

[0166] A change by the second random component to any of the frequency f, an amplitude Amp and an offset 0 of the first base function, may take place at least once every period, such a at least twice every period, such as multiple times every period. However, a change may occur either less or more frequently depending on the training prescribed.

[0167] Additionally, and / or alternatively, the step of the changes to the offset 0 and / or the amplitude (Amp) may also be varied. When varying the offset 0 and / or the amplitude Amp), closer the image comes to the one of the extreme values the probability for a small step increase. This may be implemented to avoid a step size that would move the image outside of the extreme value. Similar for the frequency f, dependent in the current frequency f, the change may be weighted to change the probability towards a small or a large increment or decrement of the frequency f.

[0168] Which of the parameters that is changed may also vary, in some examples may only one of the parameters be varied, which in some examples may two or all three be varied. Should more than two parameters be varied, they may be varied at the same time or sequentially or randomly.

[0169] Additionally, and / or alternatively, a second noise component may be used, not illustrated, wherein a frequency function, such as a sinusoidal function, a square function, triangle function or a sawtooth function, is added on said first oscillating base function. Additionally, and / or alternatively, the second noise component is a stochastic noise element, such as white noise, or a pink noise added on the first oscillating base function. This may cause random deviations which the brain could not foresee, and which will therefore improve the exercise of the eye coordination and / or the muscles around the eye compared to only using an oscillation and / or fluctuation as illustrated in Fig. 6 and 7.

[0170] In some examples only a visual parameter related to one of the first unit A and or the second unit B is manipulated using an asymmetrical fluctuation of the oscillation while a visual parameter related to the other unit is only oscillating, as illustrated in Fig. 11. In some examples are both the first and second visual parameters manipulated using an asymmetrically fluctuating oscillation. In some examples are asymmetrically fluctuating oscillation same for both the first and the second visual parameter. In some examples, are only part of an image manipulated, i.e part of the image is static while part of the image is being manipulated.

[0171] That oscillation of the first base component may be around at least one axis of a coordinate 2D-plane, or at least one axis of a coordinate 3D plane, such as the oscillation is in the X-direction, and / or in the Y-direction for the coordinate 2D-plane, or the oscillation is in the X-direction, and / or in the Y-direction, and / or in the Z-direction for the coordinate 3D-plane. The manipulation described in relation to Fig. 11 may be applied to any of the spatial parameters mentioned herein, such as to a movement, displacement, rotation, position, size, and / or scale of the visual presentation. Further, themanipulation described in relation to Fig. 11, may also be performed on a vision parameter characteristic by which image data is defined, such as one or more of focus, colour, illumination, size, orientation, or contrast.

[0172] The manipulation may be performed on a portion of the visual presentation of each unit, such as the entire visual presentation respectively

[0173] The above-described computer-based image manipulation exercises the plasticity of the brain in respect of interpretation of visual information provided uniquely for each eye, respectively. Due to the prevailing eye disorder for the individual, it is expected that the training shows a hysteresis curve between the eyes. By utilizing this effect and following its properties over time on an individual level, the efficiency of exercise will become more specified adapted for the specific individual both in respect of the eye disorder and in respect of the individual's development. Moreover, the centralized common database may incorporate for some embodiments opportunities to estimate the exercise and training efficiency based on a population taken into account of this hysteresis in the visual system, thus providing a general knowledge to optimize the training to better accommodate a normal vision.

[0174] It has further been realized that the invented apparatus and method may in addition be used for the purpose of being a support tool for diagnosing eyes related problems or disorders. Examples of diagnosis facilitated by the apparatus could be: loss of sight - for example due to retinal detachment; eyes resolution; eyes resolution with respect to depth; loss of vision due to damage or progressive destruction of or the around the macula; color vision; measure of damage to the macula - e.g. due to welding; peripheral vision; linearity of the visual field - e.g. mesh; scotopic, mesopic or photopic vision; contrast vision; etc.

[0175] Depending on how much the results of these diagnostic tests deviate from what can be seen as normal for a healthy person, they can be basis for a recommendation that the patient should attend to follow-up examination, e.g. with a visit to an eye doctor, for confirming the diagnosis made and to take treatment measures. The tests are preferably computer based. The tests are performed by the computer-based apparatus and are designed and based around the patient reacting to images being shown on the screen. The diagnostic tests are to be performed in accordance with the instructions given before each test starts. Further, the diagnostic tests are preferably designed to be self-explained so that each patient should be able to, as far as possible, perform them by him / herself without the help of an optician. The results from each diagnostic test will then be processed and presented in an appropriate form (e.g. chart, table, diagrams, graphically, etc.) to the patient and / or optician.

[0176] The diagnostic tests are either based on traditionally tests adjusted to work on the invented apparatus or are tests that the skilled person would envisage from the present disclosure, made specifically to be performed by the invented apparatus.

[0177] The present invention has been described above with reference to specific embodiments. However, other embodiments than the above described are equally possible within the scope of the invention. Different method steps than those described above, performing the method by hardware orsoftware, may be provided within the scope of the invention. The different features and steps of the invention may be combined in other combinations than those described. Visual presentations may be based on image data, such as described above, when displayed on a screen. Alternatively, the visual presentation may have a basis in real illuminated objects presented to the eye, wherein vision parameters of the visual presentation are modifiable by optical means, e.g. spectacles that have controllable refractivity, tinting, color, etc. First and / or second units may in these embodiments be lenses or prisms on a spectacle's arrangement. Alternatively, or in addition, the first and / or second units are lenses or prisms on a spectacles arrangement and wherein the control unit is arranged to pivot the lenses or prisms on the spectacles arrangement in order to manipulate the visual presentation. The scope of the invention is only limited by the appended patent claims.

Claims

CLAIMS1. An apparatus for improving eye coordination of a patient,wherein said apparatus is adapted to provide perceptual motor learning for the visual system of a patient having a first eye and a second eye, said apparatus comprisinga first unit for presenting at least one first vision parameter related to a visual presentation directed towards said first eye,a second unit for presenting at least one second vision parameter related to a visual presentation directed towards said second eye, anda processing unit for controlling said first unit and / or second unit;wherein said processing unit is adapted to control a manipulation of said first vision parameter and / or said second vision parameter, said manipulation is an oscillation of said first vision parameter and / or said second vision parameter and wherein at least one of said manipulations is an asymmetrically fluctuated oscillation.

2. The apparatus according to claim 1, wherein manipulation of said first vision parameter and / or second vision parameters comprise inducing a movement, displacement, rotation, position, size, scale of the visual presentation on at least one axis of a coordinate 2D-plane or on at least one axis of a coordinate 3D-space.

3. The apparatus according to claims 1 to 2, wherein said asymmetrically fluctuated oscillation comprising a first oscillating base component and a second random or noise component on top of said first oscillating base component.

4. The apparatus according to claim 3, wherein said first oscillating base component comprises a continuous reciprocating function, such as a sinusoidal function, a square function, triangle function or a sawtooth function.

5. The apparatus of any of claims 3 to 4, wherein said second random component comprises at least variations in one of a frequency, an amplitude and an offset of said first base function and / or said second noise component comprises a frequency function, such as a sinusoidal function, a square function, triangle function or a sawtooth function, added on said first oscillating base function and / or said second noise component is a white noise, or a pink noise added on said first oscillating base function .

6. The apparatus of any of claims 1 to 5, wherein said first unit and said second unit is part of any of a VR headset, an AR set, and MR set, and XR set.

7. The apparatus of any of claims 1 to 6, wherein said oscillation is within a first range, said first range having an extreme value, such as said extreme value is wherein a binocular vision disappears for said patient.

8. The apparatus of claim 7, wherein said process unit is configured to provide or determine a boundary value of said manipulation of said first vision parameter and said second vision parameter wherein binocular vision disappears for said patient at said boundary value, and said extreme value is less than said boundary value.

9. The apparatus of any of claim 1 to 8, wherein said manipulation of said first vision parameter and second vision parameter is done individually, such as the manipulation of said first vision parameter differ from said manipulation of said second vision parameter.

10. The apparatus of any of claims 1 to 9, wherein said vision parameters comprise spatial parameters including dimension or position of an image data.

11. The apparatus of any of claims 1 to 10, wherein said first vision parameters and / or second vision parameters are modified at least in a portion of said visual presentation, such as said entire visual presentation respectively.

12. The apparatus of any of claims 1 to 11 , wherein said manipulation is an image processing operation, and wherein said visual presentation is based on image data; and wherein said image data is identical image data for said first unit and said second unit, or wherein said image data is non-identical image data for said first unit and said second unit, and wherein said image data is one of a picture, a movie, a game or any other arbitrary image data displayable by electronic means, and wherein said image data optionally has an additional interactive audio component.

13. The apparatus of any of claims 1 to 12, wherein said first vision parameters and / or second vision parameters are a characteristic by which image data is defined, such as one or more of focus, colour, illumination, size, orientation, or contrast.

14. A computer program for improving eye coordination by providing perceptual motor learning for the visual system of a patient having a first and a second eye comprising instructions which, when the program is executed by a computer, cause the computer to carry out steps:presenting at least one first vision parameter related to a visual presentation directed towards said first eye, and / orpresenting at least one second vision parameter related to a visual presentation directed towards said second eye; andcontrolling a manipulation of said first vision parameter and / or said second vision parameter, said manipulation is an oscillation of said first vision parameter and / or said second vision parameter and wherein at least one of said manipulations is an asymmetrically fluctuated oscillation.

15. The use of any of claims 1 to 14 for improving binocular vision.

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